Warding Breath to Nowi +2

what other skills does the nowi have so far?

I say go for it. I gave it to my Nowi and she has a good mixed tank ability with it. It's a solid option still. She will need Close Def 3 seal though to deal with Falchions well.

I wouldn’t. If you’re already running a +spd Nowi it’s better to capitalize on it with fury. Also what is your wpn refine? Generally Nowi is best run super def focused so she can absorb all melee, even falchion, so steady breath IMO is better than warding.